Thermae Bath Spa

You're standing on Hot Bath Street with the Georgian terraces rising behind you, about to slip into waters that have been naturally heated for two thousand years. Thermae Bath Spa is the real deal—these aren't chlorinated pools pretending to be therapeutic. The rooftop pool is the showstopper, all steaming water and Bath stone vistas, especially magical on grey afternoons when the city disappears into mist. The spa itself is sleek and contemporary, a sharp contrast to the heritage around it, but it works. Come for the thermal experience, stay because you've suddenly got two hours to kill and nowhere else you'd rather be.